For companies that provide computing and data processing services to customers, means must be provided to account for the data storage cost in addition to the data processing and computing costs in order to accurately allocate the cost of running the company's various cost centers to the customer accounts. This practice is also known as "internal charge-back."
Traditionally, data storage is provided on DASDs (direct access storage devices), tapes, optical disks, and other hardware media. The usage of each type of hardware media is monitored and recorded by utility software programs, such as IDCAMS and Dcollect by IBM (International Business Machines), and DMS/OS (Disk Management System) by Sterling Software for DASD; and TMS (Tape Management System) by Computer Associates, TMC (Tape Management Catalog) by Legent Software, and TLS (Tape Library System) by EDS (Electronic Data Systems Corporation) for tape storage devices. These utility software gather data storage utilization statistics for each storage device, which are then used to compute the number of DASD, tape cartridges, tape reels, optical disks, etc. Subsequently, the usage cost of the storage devices are computed based on the number of characters or bytes stored on these devices.
This traditional way of accounting for data storage provides no incentive to incorporate new and faster storage technology. As new electronic storage media become available and the range of data access speeds becomes broader, it is no longer as meaningful to base accounting and price determination solely on the number of cartridges, reels, characters, or bytes.
Accordingly, a need has arisen to account for and price data storage on a more accurate and realistic level that is not significantly affected by the arrival of new data storage technology.